Prognostic influence of parapharyngeal space involvement in nasopharyngeal carcinoma

Objective To explore the prognostic influence of parapharyngeal space involvement in nasopharyngeal carcinoma (NPC).Methods From Jan.1987 to Dec. 1994, 197 previously untreated NPC patients were examined by CT scan. The prognostic factors ware evaluated by univariate and multivariate analyses on SPSS 8.0 software.Results The actual survival rate, disease free survival rate and local failure free rate were negatively affected by the presence of parapharygneal space involvement ( P =0.011 5, P =0.003 5, P = 0.036 7). The 5 year actual survival rate, disease free survival rate and local failure free rate in patients without tumor invasion to parappharyngeal space was 87.9%, 88.0% and 96.9%, respectively. The survival rate in patients with tumor invasion to prestyloid space was 75.0%, 71.2% and 93.7%, respectively. That in patients with tumor invasion to poststyloid space was 60.5%, 57.7% and 86.8%, respectively. The 5 year distant metastasis free survival rate was 88.1% in patients without poststyloid involvement as compared to 73.8% in those with poststyloid involvement. Conclusion The survival and local tumor control are affected by parapharyngeal space involvement. Distant metastasis is more likely to occur when the tumor growth involves poststyloid space.